1. Technical Field
The present application relates to a device for use in aspirating biological material, and more particularly, to a device and method for use in aspirating cells from a reservoir through a pipette during micro-manipulation techniques, such as the manipulation of an oocyte cumulus complex or an embryo, or the denuding of an oocyte complex.
2. Background Information
With the continuous advances of modern medicine, there is an ongoing need for increasingly smaller medical appliances, such as pipettes, that are suitable for carrying out medical techniques on a micro scale not previously possible. With the advent of increasingly smaller appliances, there is a corresponding increase in the need for tools or other devices suitable for use in association with the appliances.
As a part of this trend toward micro-medicine, the use of small diameter pipettes that are suitable for aspirating and/or delivering very small cells and/or volumes has dramatically increased. One example of a field of medicine that has experienced an increased use of such micro-size pipettes is the field of fertility treatment. Pipettes used in this field are typically used in micro-treatment techniques, such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). These fields, and others, continue to grow as more sophisticated micro-manipulation tools and techniques are developed.
For example, in order to carry out ICSI, a single sperm is directly injected, under microscopic vision, into the cytoplasm of an oocyte. In order to prepare for this injection, the single sperm must be isolated, and aspirated into a microinjection pipette. Another pipette is used to hold the oocyte in position as the sperm is injected into the cytoplasm. Prior to injection, a denuding pipette is used to denude the cumulus mass from the oocyte. It would not be possible to perform such delicate manipulation techniques without the use of reliable micro-scale devices, such as the described pipettes.
Pipettes for aspirating cells for use in micro-manipulation techniques are known in the art. Typically, a bulb is attached to the proximal end of the pipette to supply a suction force sufficient for aspirating the cells from a sample dish through the distal end of the pipette. Many such bulbs comprise rigid or semi-rigid elongated structures that the operator holds in his or her hand in the nature of a pencil. These bulbs are often inconvenient to use, and frequently require the operator to maintain a sufficient suction force (not too small, not too great) on the pipette while holding the bulb at an inconvenient angle. When many samples are to be aspirated, this repetitive action may cause strain to the operator. In addition, it is often difficult to control the amount of sample media aspirated into the pipette.
The pipette can also be attached to a rigid handle design that includes, e.g., a stylet wire that protrudes into the pipette. By actuating the wire up and down, suction force sufficient for aspirating the cells may be created. Additionally, it may be necessary for the operator to use digits (i.e., fingers and/or thumb) on each hand to insure that the pipette is properly positioned, and that a proper amount of suction force can be applied through the bulb.
It is desired to provide a device for use with a pipette that facilitates aspiration procedures practiced in the art. It is particularly desired to provide such a device and a method for use with pipettes suitable for use in micro-manipulation procedures, such as IVF and ICSI.